Electrical controlling apparatus



(No Model.)

0.1-1. 8u A. P. PIEPER. ELECTRICAL ONTROLLING APPARATUS.

No'. 575,573, Patented Jan. 19,1897.

Inventors:

OSCAR H. PIEPER AND ALPHONSE F.

PIEPER, OF SAN JOS, CALIFORNIA.

ELECTRICAL CONTROLLING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 575,573, dated January 19, 1897'.

Application filed December 19, 1895.

To all whom it may concern:

Be it known that we, OSOARII. PIEPER and ALPHONSE F. PIEPER, citizens of the United States, and residents of the city of San Jos, county of Santa Clara, and State of California, have invented certain new and useful Improvements in Controlling Apparatus for Electric Motors; and we hereby declare the following specification and the drawings therewith to be a complete description of our improvements, with the manner of their construction and operation.

Our invention relates to devices for controlling electric motors, especially those employed to operate dental apparatus, and to stopping,l starting, reversing, and controlling the speed of such motors by means of a pedal and oscillating switch-bar analogous in some respects and an improvement on the invention described in Letters Patent No. 541,500, granted to us on the 25th day of June, 1895, for improvements in electrical con trolling apparatus.

Our present improvements consist in improved mechanism for automatically adjusting the pedal and switch mechanism to its central or neutral position, to an improved arrangement of the rheostat elements for stopping, starting, and reversing the motor, also for arresting suddenly its momentum when revolving in either direction by utilizing said momentum to perform work and thereby arresting its motion.

Our invention consists in various mechanical and electric devices and their arrangement, as shown in the drawings and set forth in the claims at the end of this specification.

The objects of our improvements are a more eflicient and sudden control of electric motors employed in dental operations, in which such control is desirable and essential for many kinds of operations.

In the drawings, Figure 1 is a central vertical section through a cont-rolling apparatus made according to our invention. Fig. 2 is a whole plan view of Fig. 1 with the top cover removed. Fig. 3 is an enlarged plan on the line x y of Fig. 1.

Similar letters of reference are employed to designate like parts in lthe different figures of the drawings.

The main containing-case A is preferably Serial No. 572,824. (No modela made of metal, with a projecting base Iv, adapt-ed to stand on a floor, a mass M being added to increase the weight and thus resist by friction the turning strain of the footpedal K. In the center is a partially revolving or oscillating spindle F, to the top of which is attached a lever II, formed integrally with the pedal K, movable to the right or left through an arc, as indicated at T' T2 in Fig. 2.

When the pedal K and lever II are moved to the right or left, the motor Q3 is, by reason of electrical functions to be hereinafter eX- plained, started in either direction accordingly, and when the pedal K is released the lever H is at once moved to its central or neutral position by means of the jaws G G2, operated by the coil-spring I, as seen in Fig. 2.

The jaws or levers G' G2 are pivoted at a a and rest against stop-pins c e, also against the lever H, as seen in Fig. 2, so that when either of the jaws G/ or G2 are moved by the lever II the other jaw remains stationary, the spring I acting for either motion and returning the lever I-I, when released, to its central position.

The lever or pedal K can be provided with stops or locking devices to hold it at any desired point in its range, but such devices, not

forming a part of my present invention, are not included in the drawings herewith.

On the stem F is fixed a switch-bar L, provided with brushes m, n, and p, that connect with and transfer current to various contactplates in the system designated O, with numerals from 1 to 1S, connected by means of wires marked with the letter Pand numerals 1 to 10, as will appear hereinafter.

Brush n is insulated from switch-bar L, and brushes m and p are in direct contact therewith.

V and V2 are cells of au electric battery to supply current, and Q3 the armature or commutator of an electric motor having brushes Q/ Q2and main connecting-wires P2 and P2, as seen in Fig. 3.

IVe will now proceed to describe the course of the electric current when the'bar L is in the position corresponding to that indicated at T2 in Fig. 2, or an intermediate position from the center toward T2, and to operate the motor Q2 in the direction of the arrow thereon. 1' In this position of the various elements current from the battery V' V2 passes from IOO the positive poles ol the battery V V3 through the wire P to the inain ease A, through the stein F, bar L, and brush p to the plate OS, then troni the plate O1S through the wire Is to plate O and the binding-post S and through the wire P2 to the brush Q' ot the armature Q3; then through the armature (23110 the brush Q?, through the wire l):3 to the binding-post Si", thence to plate O and across the brnsha, which is insulated troni bar L, to plate Ot, thence to the binding-post S2, and returns to the negative poles of the battery V' V2 by the wire l, thus forming the armature-circuit. Tracing now the `Field-current: l'leginning at the battery V' le"V2 and following over the wire P', through the main case A, stein l?, and switch-bar L, and tothe brush m. From the brush in the current follows to the plates O, O12, Om, or O, as the position of the lever H and consequent position ot the bar L and brush m inay determine. lf the brush m rests on plates O1l or O9, then the current passes directly to the field-winding by way of the wire 1"", but if on plates O12 O13 O1l or corresponding ones OH O7( then the current in ust pass through varying resist-ance, (shown at V in Fig. l; also shown connected between the plates 0' and Og, and OT and O, liig. 3.) This resistance inserted into the field-circuit, it will be understood, regulates the strength ot the field-inagn ets, and consequently the speed of the armature. The weaker the :field-inagnets the higher the speed, and vice versa. Atter passing through the plates Ou andl O9 or through the whole or seine portion ot' the resistance-coils V the Yfield-circuit then passes over the wire l. to the motor-field lV, through this field to the wire PG, connecting with wire PL at the junction X in Fig. 3, thence by the wire Plagain to the negative poles of the battery V' V2. lt will be understood without retracing these currents that by moving the pedal K, lever Il, and switch-bar L to the position indicated by 'l" in lfig. 2 the armaturecurrent will be reversed accordingly, the iieldcurrent remaining in the direction that has been pointed ont.

lVhen the lever ll and the switch-bar L are suddenly inoved to their central or neutral position and the armature Q3 is in rapid inotion and would continue to revolve but for the Afact that as soon as the brush p reaches the plates O1T and Ol, the armature is placed on short circuit and the held-magnets are at full strength. Consequently it instantly comes to rest.

le are aware that short-circuiting an arniatnre for sudden stop has been done before, but always in combination with a resistance in either the ileld or armature circuit, and very often in both. In this instance we have so designed the electrical details that all addition of resistance is unnecessary and we get the full benciit oll the dynamo et'l'ect. rlhe direction of the current at the tiine ot the short-circuit is as follows: XVhen the brush p has passed the plate O1S or the plate OL", as the case may be, it bridges over O1G and O, this making a closed circuit on the armature and no connection with the battery Y Y, as we will now trace. Coniniencin g atthebrush Q', through the wire l to the bin dingpost S and plate O5, then through the wire flf" to the plate Ol, through the brush p to the plate 0"', and through the wire P to the plate then through the binding-post Si and the wire li back to the armature -brush Q3 without resistance in the circuit. Vrhile the brush y is passing over the central plates Ol and 01", and thereby closing the only gap between the two armattire-terminals, the brush in rc s on the plate Ou or O, and in this position the field-magnets are at t'ull strength until the segment O10 is reached, when no current llews and the armature is at rest. in this nianner it will be soen that the armature Qi' will be suddenly stopped without t'rictional or brak c devices and the whole apparatus simplilied as well as better adapted to its purposes.

Having thus described the nature and objects ol. our inventionand the manner ol' `applying the saine, what we clainl as new, and, desire to secure by Letters latent, is-- l. In an eleetrie-niotor-controlling apparatus, the combination with the niain contain,- ing-case, oi.' a vertical spindle, a fixed switchbar on said spindle, a series ot contacts surrounding the spindle, contact-segments Ol" and O, whereby integral brush P short-circuits the arinature-terminals when approaching the central position.

In an electric-inotor-controlling apparatus, the combination with the inain containing-case, ol' a vertical spindle, a :fixed switchbar on said spindle, a series et contacts surrounding the spindle, contacts O and O11 et' greater width than the adjoining ones, so that the Held-magnets remain at :t'ull strength sul'- iiciently long to bring the armature to a stop bet'ore brush m reaches neutral segment O.

3. ln an electric controlling apparatus, an oscillating spindle, a fixed switch-baron said spindle, integral. brushes m, and Vy1 and an insulated brush n on said switch-bar, a series ot' contactplates surrounding the spindle, and a levcrl'or operating the spindle, so that when the actuating-pedal is in its central or neutral position the held-magnets rcinain at full strength.

In testimony whereof we have hereunto atxed our signatures in the presence et two witnesses.

OSCAR Il. lIIlPElt. ALPHONSE F. Plllllt. liiitnesses as to Oscar ll. Pieper:

FRANK Rir'rnn, (J1-nis. W. FE1-irte. lVitnesses as to A. F. liepcr:

D. D. TENNYSON, E. li. WEMrLn.

IlO 

